420sel won't take fuel and accelerate
 

i have a 86 420sel that will start and idle but will not accelerate,dies but will restart, how do i go about testing for problem? fuel pressures are okay!
manual says there is a relay that you can stick fuse into to get a code readout but cannot find it? there is one on firewall with fuse in it but it seems to control o2 sensor and light! thanks